Granular verisimilitude

You know you have a good editor when they point out that the narratively-necessary-but-totally-arbitrary-8-digit number in your novel manuscript is unlikely to have the unique digits you thought would make it appear random because among the 100 million 8-digit numbers, there are only about 1.8 million whose digits are all different. So your number is an outlier in that particular sense; not only might the reader find it hard to imagine that anyone could know a number to that precision, but it smells like a made-up number.

Engineering the suspension of disbelief is all in the details.

Complement with a brief anatomy of story, the surprising plausibility of Russian Doll, and my best book recommendations.